diff --git a/app/controllers/api/v1/webhooks/social_inbox_controller.rb b/app/controllers/api/v1/webhooks/social_inbox_controller.rb
index c40857e0..bdf359d2 100644
--- a/app/controllers/api/v1/webhooks/social_inbox_controller.rb
+++ b/app/controllers/api/v1/webhooks/social_inbox_controller.rb
@@ -125,8 +125,9 @@ module Api
             o.save!
 
             # XXX: el objeto necesita ser guardado antes de poder
-            # procesarlo
-            ::ActivityPub::FetchJob.perform_later(site: site, object: o) unless object_embedded?
+            # procesarlo.  No usamos GlobalID porque el tipo de objeto
+            # cambia y produce un error de deserialización.
+            ::ActivityPub::FetchJob.perform_later(site: site, object_id: o.id) unless object_embedded?
           end
         end
 
diff --git a/app/jobs/activity_pub/fetch_job.rb b/app/jobs/activity_pub/fetch_job.rb
index e3fef993..6a4d163b 100644
--- a/app/jobs/activity_pub/fetch_job.rb
+++ b/app/jobs/activity_pub/fetch_job.rb
@@ -11,8 +11,11 @@ class ActivityPub
   class FetchJob < ApplicationJob
     self.priority = 50
 
-    def perform(site:, object:)
+    def perform(site:, object_id:)
       ActivityPub::Object.transaction do
+        object = ::ActivityPub::Object.find(object_id)
+
+        return if object.blank?
         return if object.activity_pubs.where(aasm_state: 'removed').count.positive?
 
         response = site.social_inbox.dereferencer.get(uri: object.uri)